Battery backup for lighting system

ABSTRACT

The described embodiments relate to systems, methods, and apparatuses for providing a lighting system that includes backup light emitting diodes (LEDs) that are incorporated into a primary array of LEDs of the lighting system. The backup LEDs can be illuminated when a utility power source for the lighting system becomes unavailable. The backup LEDs can operate from a backup power supply, which can be charged from the utility power source, when the utility power source is available. Furthermore, charging of the backup power supply can be temperature dependent, in order that the backup power supply and/or the charging circuit can be protected from damage caused by operating such components out of an operating specification.

TECHNICAL FIELD

The embodiments described herein generally relate to lighting systems.Specifically, the embodiments set forth provide lighting systems thatinclude backup LEDs that are part of an array of LEDs that are also usedduring a normal operation of the lighting system.

BACKGROUND

Lighting systems can be exposed to a variety of environmental conditionsthat can affect operations of the lighting systems. For instance,lighting systems that operate in extreme temperatures can occasionallymalfunction as a result of changes in conductivity of differentcomponents within the lighting system. Furthermore, environmentalconditions can also affect external features that support thefunctionality of the lighting systems. Such external features caninclude utility power systems, which can be susceptible to outagescaused by weather and other environmental conditions. If a lightingsystem is not designed to handle such outages, the lighting system cancease operations, or at least operate inefficiently during outages.

SUMMARY

The described embodiments relate to systems, methods, and apparatus forproviding a backup battery mode for a lighting device. In someimplementations, a method implemented by one or more processors is setforth. The method can include causing a supply signal to be provided toa first set of light emitting diodes (LEDs) and a second set of LEDs ofa lighting device. A subset of the first set of LEDs can correspond tobackup LEDs that are connected to a backup battery of the lightingdevice. The method can also include determining that a power source forthe supply signal is at least temporarily unavailable. The power sourcecan be connected to the backup LEDs at a node to which the backupbattery is connected. The method can further include causing the backupbattery to provide a backup supply signal to the backup LEDs of thefirst set of LEDs. The backup supply signal can bypass LEDs of the firstset of LEDs that are excluded from the backup LEDs, at least based on anarrangement of the backup LEDs. In some implementations, the method canalso include determining that an ambient temperature at a location ofthe lighting device is outside of an operating temperature range for thebackup battery, and causing the backup battery to provide lesselectrical current to the backup LEDs in response to the ambienttemperature being outside of the operating temperature range for thebackup battery. In other implementations, the method can include,subsequent to the backup battery providing the backup supply signal tothe backup LEDs, determining that the power source is available forproviding power to the lighting device, and determining that an ambienttemperature at a location of the lighting device is within an operatingtemperature range of backup battery charging circuit of the lightingdevice, and causing the power source to charge the backup battery.Furthermore, the method can include causing the power source to providepower to the first set of LEDs and the second set of LEDs while alsocharging the backup battery. The lighting device first set of LEDsoperate at a different color temperature than the second set of LEDs. Aportion of the first set of LEDs that excludes the backup LEDs caninclude more resistors than a separate portion of the first set of LEDscorresponding to the backup LEDs. The LEDs of the first set of LEDs thatare excluded from the backup LEDs are arranged to direct the supplysignal from to the backup LEDs.

In yet other embodiments, a system is set forth as including a first setof LEDs that includes backup LEDs arranged as a subset of the first setof LEDs, and a second set of LEDs that is separately controllable fromthe first set of LEDs. The system can also include one or more sensorsconfigured to provide sensor data associated with an operatingenvironment of the first set of LEDs and the second set of LEDs, and abackup power supply configured to provide a backup supply signal to thebackup LEDS. The backup power supply can be connected to the first setof LEDs in an arrangement that is configured to electrically isolate thebackup supply signal from LEDs that are excluded from the backup LEDs inthe first set of LEDs. The system can also include a controllerconnected to the sensor, the first set of LEDs, and the second set ofLEDs. The controller can be configured to cause the backup power supplyto receive a charge signal when the sensor data is within an operatingthreshold of the backup power supply and throttle the charge signal whenthe sensor data is outside of the operating threshold. The sensor datacan correspond to a temperature of the backup power supply or anenvironment of the backup power supply. Furthermore, the one or moresensor can include a motion sensor configured to be responsive to motionnear the first set of LEDs or the second set of LEDs. In someimplementations, the controller is further configured to: (i) cause thefirst set of LEDs to operate from a utility power source when an amountof motion detected by the motion sensor is within a motion threshold,and (ii) cause both the first set of LEDs and the second set of LEDs tooperate from the utility power source when the amount of motion detectedby the motion sensor is outside of the motion threshold. The backupsupply signal and a utility supply signal from the utility power sourcecan be received by the backup LEDs at a common node of the first set ofLEDs. A resistance of a portion of the first set of LEDs correspondingto the backup LEDs can be less than a separate resistance of separateportion of the first set of LEDs.

In yet other implementations, a non-transitory computer readable mediumis set forth as storing instructions that, when executed by one or moreprocessors, cause the one or more processors to perform steps thatinclude causing a first set of LEDs of a lighting device to operatebased on a first pulse width modulated (PWM) signal generated at thelighting device. The steps can also include determining, based on sensordata provided by one or more sensors of the lighting device, that amotion event has occurred proximate to the lighting device, and causinga second set of LEDs of the lighting device to operate in response tothe motion event, wherein the second set of LEDs are operated accordingto a second PWM signal that is different than the first PWM signal. Thesteps can further include determining that a utility power signal, fromwhich the first PWM signal and the second PWM signal are generated, istemporarily unavailable, and causing backup LEDs, which are a subset ofthe first set of LEDs, to operate from a backup battery that isconfigured to provide current for a third PWM signal, which operatesaccording to a duty cycle at which the first PWM signal operates. Theduty cycle at which the first PWM signal and the third PWM signaloperates is an inverse of a different duty cycle at which second PWMsignal operates. In some implementations, the first set of LEDs and thesecond set of LEDs are concurrently illuminated in response to thedetection of the motion event. Furthermore, the backup LEDs can beexclusively illuminated in response to the determination that theutility power signal is temporarily unavailable. The second set of LEDscan provide a higher color temperature output than the first set ofLEDs. In some implementations, the one or more sensors can include atemperature sensor and the steps can further include: determining thatthe utility power signal is available, determining that an operatingtemperature of a charging circuit for the backup battery is within atemperature threshold accessible to the one or more processors, andcausing the charging circuit to provide a charging signal to thebattery. The utility power signal can be determined to be availablewithin a threshold time period from the motion event, and the steps canfurther include: causing the first set of LEDs and the second set ofLEDs to be illuminated simultaneously from the utility power signal.

For purposes of the instant specification the term “security lightingsystem” or “lighting system” is used herein to refer to animplementation or arrangement of one or more linked lighting units in aparticular form factor, assembly, or package. The term “security light”or “lighting unit” is used herein to refer to an apparatus including oneor more light sources of same or different types. A given lighting unitcan have any one of a variety of mounting arrangements for the lightsource(s), enclosure/housing arrangements and shapes, and/or electricaland mechanical connection configurations. Additionally, a given unitoptionally can be associated with (e.g., include, be coupled to and/orpackaged together with) various other components (e.g., controlcircuitry) relating to the operation of the light source(s).

Additionally the term “controller” is used herein generally to describevarious apparatus relating to the operation of one or more lightsources. A controller can be implemented in numerous ways (e.g., such aswith dedicated hardware) to perform various functions discussed herein.A “processor” is one example of a controller, which employs one or moremicroprocessors that may be programmed using software (e.g., microcode)to perform various functions discussed herein. A controller may beimplemented with or without employing a processor, and also may beimplemented as a combination of dedicated hardware to perform somefunctions and a processor (e.g., one or more programmed microprocessorsand associated circuitry) to perform other functions. Examples ofcontroller components that may be employed in various embodiments of thepresent disclosure include, but are not limited to, conventionalmicroprocessors, application specific integrated circuits (ASICs), andfield-programmable gate arrays (FPGAs).

In various implementations, a processor or controller may be associatedwith one or more storage media (generically referred to herein as“memory,” e.g., volatile and non-volatile computer memory such as RAM,PROM, EPROM, and EEPROM, floppy disks, compact disks, optical disks,magnetic tape, etc.). In some implementations, the storage media may beencoded with one or more programs that, when executed on one or moreprocessors and/or controllers, perform at least some of the functionsdiscussed herein. Various storage media may be fixed within a processoror controller or may be transportable, such that the one or moreprograms stored thereon can be loaded into a processor or controller soas to implement various aspects of the present invention discussedherein. The terms “program” or “computer program” are used herein in ageneric sense to refer to any type of computer code (e.g., software ormicrocode) that can be employed to program one or more processors orcontrollers.

It should be appreciated that all combinations of the foregoing conceptsand additional concepts discussed in greater detail below (provided suchconcepts are not mutually inconsistent) are contemplated as being partof the inventive subject matter disclosed herein. In particular, allcombinations of claimed subject matter appearing at the end of thisdisclosure are contemplated as being part of the inventive subjectmatter disclosed herein. It should also be appreciated that terminologyexplicitly employed herein that also may appear in any disclosureincorporated by reference should be accorded a meaning most consistentwith the particular concepts disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference characters generally refer to the sameparts throughout the different views. Also, the drawings are notnecessarily to scale, emphasis instead generally being placed uponillustrating the principles of the invention.

FIG. 1 illustrates a perspective view of a lighting unit that includesmultiple sets of LEDs that illuminate according to different operatingconditions.

FIG. 2 illustrates a system for operating a security lighting systemaccording to some of the embodiments discussed herein.

FIG. 3 illustrates a diagram that provides a lighting system thatincludes backup LEDs that are part of a primary set of LEDs, and can beseparately illuminated during a backup power mode of the lightingsystem.

FIG. 4 illustrates a method for operating a lighting system in a backuppower mode.

FIG. 5 illustrates a method of operating a lighting system according todifferent PWM signals.

FIG. 6 is a block diagram of an example computer system.

DETAILED DESCRIPTION OF THE INVENTION

The described embodiments relate to systems, methods, and apparatusesfor controlling lights in a security lighting system according towhether grid power is available to the security lighting system. Asecurity light can illuminate in response to a variety of stimulus inorder to illuminate areas of interest when certain actions are occurringat those areas. An example of such stimulus can include motion orchanges in ambient light. Unfortunately, should a power outage occur,many security lights would no longer be able to sense such stimulus andprovide power to their lights. Moreover, in the event that a light of asecurity lighting device malfunctions, the security light may not haveany backup for providing light in case of an emergency. However, thepresent disclosure provides security lighting systems with a backupbattery and a backup array of light emitting diodes (LEDs), along withcircuitry for preserving the backup battery, and controlling when thebackup array of LEDs will be active.

The security lighting system provided herein can be powered by analternating current (AC) power source, such as a utility power source,when operating in a normal power mode. Additionally, the securitylighting system can be powered by a direct current (DC) power source,such as a backup battery power source, when operating in a backup powermode. The security lighting system can include an LED array with a firstset of LEDs that can be powered by the AC power source during the normalpower mode. Furthermore, a second set of LEDs of the LED array can bepowered by the DC power source during the backup power mode. Thesecurity lighting system can include a controller that is connected to amotion sensor and/or an ambient light sensor of the security lightingsystem. Signals from the motion sensor and/or the ambient light sensorcan be used by the controller to control the first set of LEDs and thesecond set of LEDs. Additionally, the controller can modify theoperations of the first set of LEDs and the second set of LEDs accordingto whether the security lighting system is operating in the normal powermode or the backup power mode.

When operating in the backup power mode, the second set of LEDs canilluminate in response to signals from a motion sensor and/or ambientlight sensor, and the illumination time can be limited to conservebattery power. The second set of LEDs can illuminate as long as motionis sensed and/or as long as an amount of ambient light detected isoutside of a threshold. In some embodiments, the first set of LEDs andthe second set of LEDs can include at least some of the same LEDs. Inother words, some LEDs that are used during the normal power mode canalso be used during the backup power mode. In other embodiments, theLEDs operating in the backup power mode can be a subset of the LEDsoperating in the normal power mode. In yet other embodiments, the LEDarray can operate at a first level of luminance in the normal power modeand a second level of luminance, which consumes less energy than thefirst level of luminance, during the backup power mode.

The second set of LEDs can be reserved for operation during the backuppower mode, and/or can be used during a light boost mode. For example,the first set of LEDs can operate at a first level of brightness orcolor temperature when a first condition is satisfied, and a secondlevel of brightness or color temperature when a second condition issatisfied. Additionally, the second set of LEDs can operate incombination with the first set of LEDs when a third condition issatisfied. Each of the conditions can be satisfied based on the signalsthat are received from sensors of the security lighting system, aselection made by a user of the security lighting system, and/or anyother input or change occurring at the security lighting system.

When the first set of LEDs or the second set of LEDs are operating in abackup power mode, or a dim power mode, adjustments to a colortemperature of the first set of LEDs or the second set of LEDs can belimited. Furthermore, adjustments to the color temperature of the firstset of LEDs and the second set of LEDs can be made using a PWM signal,and an inverse of the PWM signal. For instance, a color temperature ofthe first set of LEDs (e.g., 5000K LEDs) can be set according to a PWMsignal that is provided to the first set of LEDs. The PWM signal can,for example, have a duty cycle of 70% when operating the first set ofLEDs. Furthermore, when operating the second set of LEDs, an inverse ofthe PWM signal can be used to control the color temperature. Therefore,the duty cycle of the PWM signal to the second set of LEDs can be, forexample, 30%.

The security lighting system can include a battery charger for chargingthe backup battery of the security lighting system. In order to preservea useful lifetime of the battery, the battery charger can be preventedfrom charging the battery when an ambient temperature and/or batterytemperature measured by the security lighting system is outside of aspecified temperature threshold. In some embodiments, at least some ofthe LEDs in the LED array can be prevented from operating when theambient temperature and/or battery temperature measured by the securitylighting system is outside of a specified temperature threshold. Itshould be noted that the battery or batteries that operate during thebackup battery mode can be rechargeable or non-rechargeable.

The security lighting system can include a driver that receives AC powerfrom a grid power source and converts the AC power into usable power bythe LED array. The driver can also provide power to a controller that isconnected to one or more sensors and a DC charging circuit for chargingthe backup battery of the security lighting system. Additionally, thecontroller can detect when AC power is no longer available to the driveras a result of, for example, an outage, and initialize the backupbattery for powering the security lighting system. When the controllerdetermines that AC power is no longer available, the controller can alsoswitch the security lighting system to operating a backup set of LEDs inorder to preserve the main LEDs (e.g., the first set of LEDs) of the LEDarray.

In the following detailed description, for purposes of explanation andnot limitation, representative embodiments disclosing specific detailsare set forth in order to provide a thorough understanding of theclaimed invention. However, it will be apparent to one having ordinaryskill in the art having had the benefit of the present disclosure thatother embodiments according to the present teachings that depart fromthe specific details disclosed herein remain within the scope of theappended claims. Moreover, descriptions of well-known apparatus andmethods may be omitted so as to not obscure the description of therepresentative embodiments. Such methods and apparatus are clearlywithin the scope of the claimed invention. For example, aspects of themethods and apparatus disclosed herein are described in conjunction witha security light unit having a housing and having one or more lightheads with various illumination sources. However, one or more aspects ofthe methods and apparatus described herein may be implemented in otherunits that have alternative configurations. For example, aspectsdescribed herein may be implemented in security light units wherein theillumination sources and/or other components are not enclosed in ahousing. Also, for example, aspects described herein may be implementedin units wherein power may be provided to one or more of the componentsof the security light unit through various electrical connections thatare not engageable with a standard illumination sources. Implementationof the one or more aspects described herein in alternatively configuredenvironments is contemplated without deviating from the scope or spiritof the claimed invention.

FIG. 1 illustrates a perspective view of a lighting unit 100 thatincludes multiple sets of LEDs that illuminate according to differentoperating conditions. The lighting unit 100 can include one or moreseparate lights (102, 104, and 106) that can be static or maneuverableto provide light in different directions. Each of the lights can includea first set of LEDs 116 and a second set of LEDs 118. The lighting unit100 can further include one or more sensors 110, which can be a motionsensor and/or an ambient light sensor. Additionally, the lighting unit100 can include multiple different power sources such as a battery 112and a utility power source 108, illustrated as a cable that can beconnected to utility power. During operation of the lighting unit 100,the power source of the lighting unit 100 can change according towhether utility power is available. For example, when there is an outageof the utility power source 108, the lighting unit 100 can operate usingthe battery 112. Furthermore, the first set of LEDs 116 and the secondset of LEDs 118 can operate independently according to various operatingconditions of the lighting unit 100. For example, the first set of LEDs116 can be a primary set and the second set of LEDs 118 can be a backupset. The second set of LEDs 118 can be powered by the battery 112 whenthe utility power source 108 is not available as a result of, forexample, a power outage. When the utility power source 108 is notavailable, the battery 112 can also power a controller that is connectedto the sensors 110. In this way, the lighting unit 100 can operate inresponse to signals from the sensors 110 when an outage occurs andlimits the availability of the utility power source 108. For example,the controller can cause the second set of LEDs 118 to illuminate usingbattery power from the battery 112 when an outage occurs and motion isdetected by the sensor 110. Furthermore, the controller can include amemory that stores timer values that govern how long the second set ofLEDs 118 will illuminate in response to a signal from the sensor 110. Insome embodiments, the timer value can be selected by a user in orderthat the user can decide how long they would like an area to beilluminated in response to motion detection.

In some embodiments, the first set of LEDs 116 and the second set ofLEDs 118 can be part of an LED array that can be powered entirely byeither the utility power source 108 or the battery 112. For example,during a dim mode of the lighting unit 100, where an ambient lightsensor 110 of the lighting unit 100 detects that there is an amount ofambient light outside of a certain threshold, the first set of LEDs 116of the LED array can be illuminated using the utility power source 108.In some embodiments, the first set of LEDs 116 can consume more powerthan the second set of LEDs 118, and provide greater illumination thanthe second set of LEDs 118. Should a power outage occur during the dimmode, the first set of LEDs 116 can be shut off and the second set ofLEDs 118 can be illuminated using the battery 112. Furthermore, shouldmotion be detected while the battery is powering the second set of LEDs118 in the dim mode, the controller can illuminate at least some of thefirst set of LEDs 116 with the second set of LEDs 118, and/or illuminatethe second set of LEDs 118 at a brighter level or different colortemperature. However, if there is no outage, the second set of LEDs 118can be illuminated only in certain modes. For example, the lighting unit100 can be switched to a light boost mode, which would employ the secondset of LEDs 118. During the light boost mode, when the lighting unit 100is being powered by the utility power source 108, each of the first setof LEDs 116 and the second set of LEDs 118 can be illuminated to theirmaximum brightness. This provides for a third operating mode, inaddition to the dim mode and the dim mode plus motion.

The battery 112 can be charged using a charging circuit that can bepowered by the utility power source 108 and/or a renewable power source,such a solar panel located on or near the lighting unit 100. Thecharging circuit can charge the battery 112 when power is available fromthe utility power source 108 and the charge of the battery 112 isoutside of a charge threshold. Furthermore, the charging circuit canstop charging the battery when the charge of the battery is within thecharge threshold or when the utility power source 108 is not available,for example, as a result of an outage. In some embodiments, the sensors110 can also include a temperature sensor for providing temperaturerelated signals to the controller for controlling the lighting unit 100.The controller can change an operation of the charging circuit accordingto a temperature measured by the temperature sensor. For example, if anambient temperature outside the lighting unit 100 and/or an internaltemperature of the lighting unit 100 are outside a temperature thresholdstored by the controller, the controller can limit an operation of thecharging circuit. In other embodiments, if an ambient temperatureoutside the lighting unit 100 and/or an internal temperature of thelighting unit 100 are outside a temperature threshold stored by thecontroller, the controller can limit an operation of the LED array. Inthis way, the charging circuit, battery 112, and/or LED array can beprotected from damage that can result from operating at highertemperatures. In some embodiments, the restrictions on operating atcertain temperatures can change when the utility power source 108 is notavailable. For example, when the utility power source 108 is notavailable and the ambient temperature and/or internal temperature isoutside of the temperature threshold, the controller can cause the firstset of LEDs 116 and/or the second set of LEDs 118 to be responsive tosignals from the sensors 110. In this way, despite there being a poweroutage, the lighting unit 100 can still illuminate when ambient light isoutside of a light threshold and/or motion is detected by a motionsensor.

FIG. 2 illustrates a system 200 for operating a security lighting system202 according to some of the embodiments discussed herein. The securitylighting system 202 can be powered by utility power 204, such as powerfrom a 120 VAC wall socket, or a backup battery 112, which can be arechargeable battery or a disposable battery. The security lightingsystem 202 is capable of switching between these power sources accordingto certain operating conditions of the security lighting system 202.Furthermore, the security lighting system 202 is capable switchingbetween lights sources according to certain operating conditions of thesecurity lighting system 202. For example, while operating in a normaloperating mode, where utility power 204 is available, a driver 208 ofthe security lighting system 202 can convert the utility power 204 tousable power by main LEDs 206. The main LEDs 206 can be part of an LEDarray of the security lighting system 202, and the LED array can alsoinclude a set of backup LEDs 214. However, in some embodiments, the mainLEDs 206 can be a separate LED array from the backup LEDs 214. The mainLEDs 206 and the backup LEDs 214 can operate at the same colortemperature or different color temperatures. For example, in someembodiments, the main LEDs 206 can include LEDs that operate at a firstcolor temperature (e.g., 3000K) and LEDs that operate at a second colortemperature (e.g., 5000K). The first color temperature LEDs of the mainLEDs 206 can illuminate during a dim mode of the security lightingsystem 202, and the second color temperature LEDs can illuminate duringa normal operating mode of the security lighting system 202.

The driver 208 can power a controller 212 of the security lightingsystem 202 from either utility power 204 or the backup battery 218. Forexample, when a power outage occurs and the utility power 204 is nolonger available, the controller 212 can detect that a loss ofelectrical power from the utility power 204 and switch the driver 208 tothe backup battery 218. The controller 212 can also use sensors 210 todetermine when to no longer operate a backup power circuit 216 of thesecurity lighting system 202. For example, at least one of the sensors210 can be a temperature sensor, and the backup power circuit 216 cancharge the backup battery 218 using power from the utility power 204.The temperature sensor can measure an ambient sensor outside thesecurity lighting system 202 and/or an internal temperature of thesecurity lighting system 202. If the ambient temperature and/or theinternal temperature is outside a temperature threshold stored by thecontroller 212, the controller 212 can prevent the backup power circuit216 from charging the battery 218. In this way, the operating lifetimeof the battery 218 can be preserved. Temperature measurements can alsobe used by the controller 212 to limit the operations of the main LEDs206 and/or the backup LEDs 214. For example, if the ambient temperatureand/or the internal temperature are outside of a temperature threshold,the controller 212 can prevent the main LEDs 206 and/or the backup LEDs214 from receiving power from the utility power 204 or the backupbattery 218.

FIG. 3 illustrates a diagram 300 that provides a lighting system 302that includes backup LEDs 308 that are part of a primary set of LEDs,and can be separately illuminated during a backup power mode of thelighting system 302. The lighting system 302 can be a security lightingsystem that can be part of, or include, one or more elements of thesecurity lighting system 202 of FIG. 2. For instance, the lightingsystem 302 can include a backup power supply 310, which can be a backupbattery or any other rechargeable power supply. The lighting system 302can also include a primary power supply 312, which can be a circuit orconnection to a utility power source (e.g., an alternating current (AC)power source). The symbols 318 provided between the backup power supply310 and backup power connection 320, and the primary power supply 312and the primary power connection 322, can indicate a direct electricalconnection or an electrical connection that includes one or morecomponents that are not illustrated.

The lighting system 302 can operate according multiple different modes,in which a first set of LEDs 304, a second set of LEDs 306, and/orbackup LEDs 308 can operate separately, or in combination, depending onthe mode governing lighting system 302. For instance, during a normaloperating mode of the lighting system 302, the entire first set of LEDs304 can be illuminated, including the backup LEDs 308. However, in someimplementations the first set of LEDs 304, except the backup LEDs 308,can be illuminated during the normal operating mode. When motion isdetected by a sensor of the lighting system 302, the backup LEDs 308 canbe illuminated with the other LEDs in the first set of LEDs 304. Inother implementations, when motion is detected by the sensor, the backupLEDs 308 can be illuminated with the other LEDs in the first set of LEDs304, as well as the second set of LEDs 306.

In response to motion being detected by one or more sensors of thelighting system 302, a time that is managed by the lighting system 302can be initialized. The timer can track an amount of time since a mostrecent motion event was detected by a sensor of the lighting system 302.When the timer reaches or exceeds a motion threshold, the LEDs that wereilluminated in response to the motion event can turned off or otherwisenot receive a supply signal. The lighting system 302 can access multipledifferent timers. The timers can be associated with times of day ofoperation of the lighting system 302, types of motion events detected bythe sensor, a mode in which the lighting system 302 is operating, and/orany other characteristic of an operation of the lighting system 302.

The lighting system 302 can include multiple different circuits thatembody the first set of LEDs 304, the second set of LEDs 306, and thebackup LEDs 308. For instance, the first set of LEDs 304 can includemultiple LEDs and resistors 314 for directing a current through thefirst set of LEDs 304 in a direction of a circuit that includes thebackup LEDs 308. The circuit that includes the backup LEDs 308 can alsoinclude multiple LEDs and resistors 314 for directing a current from theother LEDs of the first set of LEDs 304 through the LEDs of the backupLEDs 308. A first resistance of a circuit corresponding to the first setof LEDs 304, excluding the backup LEDs 308, can be higher than a secondresistance of a circuit corresponding to the backup LEDs 308.Alternatively, the first resistance can be equal to or lower than thesecond resistance.

In some implementations, a driver or other power converter of thelighting system 302 can provide multiple different pulse width modulated(PWM) signals for powering the first set of LEDs 304, the second set ofLEDs 306, and/or the backup LEDs 308. For instance, a first PWM signalcan be provided for controlling an output of the first set of LEDs 304and a second PWM signal can be provided for controlling an output of thesecond set of LEDs 306. In some implementations, the first PWM signalcan operate according to a different duty cycle than the second PWMsignal. For instance, a duty cycle of the first PWM signal can be 70%,and the second PWM signal can operate according to a duty cycle of 30%.In other implementations, the duty cycle of the second PWM signal can bean inverse of the first PWM signal. A third PWM signal can be providedfor controlling the backup LEDs 308. The third PWM signal can be thesame as the first PWM signal or the second PWM signal, or be differentthan the first PWM signal and the second PWM signal. For instance, thethird PWM signal can be the same as the first PWM signal, and alsooperate according to a duty cycle (e.g., 70%) that is an inverse of aduty cycle (e.g., 30%) of the second PWM signal.

In some implementations, the lighting system 302 can operate accordingto a full bright mode, in which the first set of LEDs 304 and the secondset of LEDs 306 can be illuminated. The full bright mode can excludeillumination of the backup LEDs 308 in order to preserve an operatinglifetime of the backup LEDs 308. In some implementations, the lightingsystem 302 can include a motion sensor and an ambient light sensor. Whenthe ambient light sensor detects an amount of light that is less than anambient light threshold, the lighting system 302 can operate in a dimmode, in which the first set of LEDs 304 (with or without the backupLEDs 308 being illuminated) are illuminated. When motion is detected atthe lighting system 302, the lighting system 302 can operate in the fullbright mode in which the first set of LEDs 304 and the second set ofLEDs 306 are illuminated (with or without the backup LEDs 308 beingilluminated). In some implementations, when motion is detected andambient light is below the ambient light threshold, the first set ofLEDs 304 and the second set of LEDs 306 can be illuminated without thebackup LEDs 308 being illuminated.

In some implementations, the lighting system 302 can operate in a backupmode. The lighting system 302 can transition from a different operatingmode to the backup mode when a utility power signal is no longerprovided to or detected by the lighting system 302. While operating inthe backup mode, a battery supply signal from the backup power supply310 can be provided to the backup LEDs 308 and bypass the other LEDs ofthe first set of LEDs 304 and the second set of LEDs 306. Whileoperating in the backup mode, the sensors of the lighting system 302 canbe operational, in order that the backup LEDs 308 can be illuminated inresponse to a motion event or a lack of ambient light. For instance,during a power outage, a utility supply signal can be unavailable to thelighting system 302 and, in response, the lighting system 302 can causethe backup power supply 310 to provide power for operating the lightingsystem 302. The backup power supply 310 can operate a motion sensor ofthe lighting system 302, and when the motion sensor detects a motionevent, the backup power supply 310 can provide a supply signal to thebackup LEDs 308 for illuminating the backup LEDs 308 for a period oftime. In some implementations, the lighting system 302 can include atemperature sensor that is responsive to temperature changes of thebackup power supply 310 (e.g., a battery), a charging circuit, and/orany other portion of the lighting system 302. Furthermore, the lightingsystem 302 can operate according to a temperature threshold. When atemperature sensed by the temperature sensor is outside of thetemperature threshold, the backup power supply 310, the chargingcircuit, and/or the lighting system 302 can be throttled in order topreserve an operational lifetime of the lighting system 302. Forinstance, because operating a battery at a high temperature can damagethe battery, it can be beneficial to throttle an output of the batterywhen the temperature reaches a temperature threshold.

The temperature sensor can be used to determine when to throttle abattery charging operation of the lighting system 302. For instance,when the utility power signal is available to the lighting system 302, abattery of the backup power supply 310 can be charged from the utilitypower signal as long as the temperature of the battery or chargingcircuit is within a temperature threshold. When the temperature of thebattery or charging circuit is outside of the temperature threshold, thebattery can be prevented from providing a supply current and/or thecharging circuit can be prevented from charging the battery. In thisway, an operational lifetime of the battery and the charging circuit canbe preserved.

FIG. 4 illustrates a method 400 for operating a lighting system in abackup power mode. The method 400 can be performed by a lighting device,a computing device, and/or any other device capable of controlling alight. The method 400 can include a block 402 of causing a supply signalto be provided to a first set of LEDs and a second set of LEDs of alighting device. The first set of LEDs can include a set of backup LEDsthat are connected to a backup battery of the lighting device. In someimplementations, the backup battery can be arranged to provide a backupsupply current exclusively to the backup LEDs, as well as any othercircuit components that can assist in providing the current the backupLEDs and operating the lighting device.

The method 400 can further include a block 404 of determining that apower source for the supply signal is at least temporarily unavailable.The supply signal can be provided by a utility power source thatprovides power to various locations in a geographic area. When an outageoccurs, the utility power source may not be available to provide powerand the lighting device can be responsive to the lack of utility power.For instance, a controller or driver of the lighting device candetermine that an amount of current, voltage, and/or power from theutility power source has fallen below a threshold. The lighting devicecan thereafter modify its operating mode to compensate for the lack ofutility power.

The method 400 can also include a step 406 of causing the backup batteryto provide a backup supply signal to the backup LEDs of the first set ofLEDs, while also causing the backup supply signal to bypass other LEDsof the first set of LEDs that do not include the backup LEDs. The backupsupply signal can bypass the other LEDs because of an arrangement of thebackup LEDs relative to the other LEDs of the first set of LEDs. Forinstance, diodes of the first set of LEDs can be arranged such that thebackup supply signal is directed away from the other LEDs. In someimplementations, a first portion of the first set of LEDs that includesthe other LEDs can have a higher resistance than a second portion of thefirst set of LEDs that includes the backup LEDs. In this way, electricalcurrent will be diverted from the other LEDs to the backup LEDs, atleast because of the path of least resistance provided by the backupLEDs.

FIG. 5 illustrates a method 500 of operating a lighting device accordingto different PWM signals. The method 500 can be performed by a lightingdevice, a computing device, and/or any other apparatus capable ofcontrolling a light. The method 500 can include a block 502 of causing afirst set of LEDs of a lighting device to operate based on a first PWMsignal generated at the lighting device. The first PWM signal canoperate according to a duty cycle that is set by a controller or adriver of the lighting device. The duty cycle can refer to an amount oftime, a ratio, or a percentage that characterizes how much time a signalis in high state compared to an amount of time the signal is in a lowstate. For instance, if a period of a signal is 1 millisecond, and thesignal is high for 0.7 milliseconds, the signal can be characterized ashaving a duty cycle of 70%.

The method 500 can also include a block 504 of determining, based onsensor data provided by one or more sensors of the lighting device, thata motion event has occurred proximate to the lighting device. The motionevent can be, for example, a person walking by the lighting device or anautomobile traveling near the lighting device. The sensor data can bepowered by a utility power source or a backup power source depending onan availability of the utility power source. Furthermore, the sensor canbe a motion sensor, which can include an infrared sensor, image sensor,audio sensor, moisture sensor, temperature sensor, and/or any othersensor capable of being responsive to movements.

The method 500 can further include a block 506 of causing a second setof LEDs of the lighting device to operate according to a second PWMsignal in response to the motion event. The second PWM signal can have aduty cycle that is different than a duty cycle of the first PWM signal.For instance, the second PWM signal can have a duty cycle (e.g., 30%)that is an inverse of the first PWM signal (e.g., 70%). In this way,operational instructions for the different sets of LEDs can be morestreamlined.

The method 500 can further include a block 508 of determining that autility power signal, from which the first PWM signal and the second PWMsignal are generated, is temporarily unavailable. The utility powersignal can be temporarily unavailable as a result of a power outage orother power interruption. The determination can be made in response to acontroller or a driver of the lighting device ceasing to receive theutility power signal, or a characteristic of the utility power signalfalling within or outside of a predetermined threshold.

The method 500 can also include a block 510 of causing backup LEDs,which are a subset of the first set of LEDs, to operate from a backupbattery that is configured to provide current for a third PWM signal.The third PWM signal can operate according to a duty cycle that is thesame or substantially similar to the duty cycle at which the first PWMsignal operates. In some implementations, the backup LEDs are directlyconnected to other LEDs of the first set of LEDs, and therefore canoperate in a backup mode, a normal mode, a bright mode, and/or a dimmode. However, in other implementations, the backup LEDs can beexclusively reserved for a backup mode in which the backup LEDs aresupplied power from a backup power supply.

FIG. 6 is a block diagram of an example computer system 610 (i.e.,computing device). Computer system 610 typically includes at least oneprocessor 614 which communicates with a number of peripheral devices viabus subsystem 612. These peripheral devices may include a storagesubsystem 624, including, for example, a memory 625 and a file storagesubsystem 626, user interface output devices 620, user interface inputdevices 622, and a network interface subsystem 616. The input and outputdevices allow user interaction with computer system 610. Networkinterface subsystem 616 provides an interface to outside networks and iscoupled to corresponding interface devices in other computer systems.

User interface input devices 622 may include a keyboard, pointingdevices such as a mouse, trackball, touchpad, or graphics tablet, ascanner, a touchscreen incorporated into the display, audio inputdevices such as voice recognition systems, microphones, and/or othertypes of input devices. In general, use of the term “input device” isintended to include all possible types of devices and ways to inputinformation into computer system 610 or onto a communication network.

User interface output devices 620 may include a display subsystem, aprinter, a fax machine, or non-visual displays such as audio outputdevices. The display subsystem may include a cathode ray tube (CRT), aflat-panel device such as a liquid crystal display (LCD), a projectiondevice, or some other mechanism for creating a visible image. Thedisplay subsystem may also provide non-visual display such as via audiooutput devices. In general, use of the term “output device” is intendedto include all possible types of devices and ways to output informationfrom computer system 610 to the user or to another machine or computersystem.

Storage subsystem 624 stores programming and data constructs thatprovide the functionality of some or all of the modules describedherein. For example, the storage subsystem 624 may include the logic toperform selected aspects of method 400, method 500, method 600, and/orto implement one or more of the lighting unit 100, security lightingsystem 202, controller 212, driver 208, lighting system 302, and/or anyother element discussed herein.

These software modules are generally executed by processor 614 alone orin combination with other processors. Memory 625 used in the storagesubsystem 624 can include a number of memories including a main randomaccess memory (RAM) 630 for storage of instructions and data duringprogram execution and a read only memory (ROM) 632 in which fixedinstructions are stored. A file storage subsystem 626 can providepersistent storage for program and data files, and may include a harddisk drive, a floppy disk drive along with associated removable media, aCD-ROM drive, an optical drive, or removable media cartridges. Themodules implementing the functionality of certain implementations may bestored by file storage subsystem 626 in the storage subsystem 624, or inother machines accessible by the processor(s) 614.

Bus subsystem 612 provides a mechanism for letting the variouscomponents and subsystems of computer system 610 communicate with eachother as intended. Although bus subsystem 612 is shown schematically asa single bus, alternative implementations of the bus subsystem may usemultiple busses.

Computer system 610 can be of varying types including a workstation,server, computing cluster, blade server, server farm, or any other dataprocessing system or computing device. Due to the ever-changing natureof computers and networks, the description of computer system 610depicted in FIG. 6 is intended only as a specific example for purposesof illustrating some implementations. Many other configurations ofcomputer system 610 are possible having more or fewer components thanthe computer system depicted in FIG. 6.

While several inventive embodiments have been described and illustratedherein, those of ordinary skill in the art will readily envision avariety of other means and/or structures for performing the functionand/or obtaining the results and/or one or more of the advantagesdescribed herein, and each of such variations and/or modifications isdeemed to be within the scope of the inventive embodiments describedherein. More generally, those skilled in the art will readily appreciatethat all parameters, dimensions, materials, and configurations describedherein are meant to be exemplary and that the actual parameters,dimensions, materials, and/or configurations will depend upon thespecific application or applications for which the inventive teachingsis/are used. Those skilled in the art will recognize, or be able toascertain using no more than routine experimentation, many equivalentsto the specific inventive embodiments described herein. It is,therefore, to be understood that the foregoing embodiments are presentedby way of example only and that, within the scope of the appended claimsand equivalents thereto, inventive embodiments may be practicedotherwise than as specifically described and claimed. Inventiveembodiments of the present disclosure are directed to each individualfeature, system, article, material, kit, and/or method described herein.In addition, any combination of two or more such features, systems,articles, materials, kits, and/or methods, if such features, systems,articles, materials, kits, and/or methods are not mutually inconsistent,is included within the inventive scope of the present disclosure.

All definitions, as defined and used herein, should be understood tocontrol over dictionary definitions, definitions in documentsincorporated by reference, and/or ordinary meanings of the definedterms.

The indefinite articles “a” and “an,” as used herein in thespecification and in the claims, unless clearly indicated to thecontrary, should be understood to mean “at least one.”

The phrase “and/or,” as used herein in the specification and in theclaims, should be understood to mean “either or both” of the elements soconjoined, i.e., elements that are conjunctively present in some casesand disjunctively present in other cases. Multiple elements listed with“and/or” should be construed in the same fashion, i.e., “one or more” ofthe elements so conjoined. Other elements may optionally be presentother than the elements specifically identified by the “and/or” clause,whether related or unrelated to those elements specifically identified.Thus, as a non-limiting example, a reference to “A and/or B”, when usedin conjunction with open-ended language such as “comprising” can refer,in one embodiment, to A only (optionally including elements other thanB); in another embodiment, to B only (optionally including elementsother than A); in yet another embodiment, to both A and B (optionallyincluding other elements); etc.

As used herein in the specification and in the claims, “or” should beunderstood to have the same meaning as “and/or” as defined above. Forexample, when separating items in a list, “or” or “and/or” shall beinterpreted as being inclusive, i.e., the inclusion of at least one, butalso including more than one, of a number or list of elements, and,optionally, additional unlisted items. Only terms clearly indicated tothe contrary, such as “only one of” or “exactly one of,” or, when usedin the claims, “consisting of,” will refer to the inclusion of exactlyone element of a number or list of elements. In general, the term “or”as used herein shall only be interpreted as indicating exclusivealternatives (i.e. “one or the other but not both”) when preceded byterms of exclusivity, such as “either,” “one of,” “only one of,” or“exactly one of” “Consisting essentially of,” when used in the claims,shall have its ordinary meaning as used in the field of patent law.

As used herein in the specification and in the claims, the phrase “atleast one,” in reference to a list of one or more elements, should beunderstood to mean at least one element selected from any one or more ofthe elements in the list of elements, but not necessarily including atleast one of each and every element specifically listed within the listof elements and not excluding any combinations of elements in the listof elements. This definition also allows that elements may optionally bepresent other than the elements specifically identified within the listof elements to which the phrase “at least one” refers, whether relatedor unrelated to those elements specifically identified. Thus, as anon-limiting example, “at least one of A and B” (or, equivalently, “atleast one of A or B,” or, equivalently “at least one of A and/or B”) canrefer, in one embodiment, to at least one, optionally including morethan one, A, with no B present (and optionally including elements otherthan B); in another embodiment, to at least one, optionally includingmore than one, B, with no A present (and optionally including elementsother than A); in yet another embodiment, to at least one, optionallyincluding more than one, A, and at least one, optionally including morethan one, B (and optionally including other elements); etc.

It should also be understood that, unless clearly indicated to thecontrary, in any methods claimed herein that include more than one stepor act, the order of the steps or acts of the method is not necessarilylimited to the order in which the steps or acts of the method arerecited.

In the claims, as well as in the specification above, all transitionalphrases such as “comprising,” “including,” “carrying,” “having,”“containing,” “involving,” “holding,” “composed of,” and the like are tobe understood to be open-ended, i.e., to mean “including but not limitedto”. Only the transitional phrases “consisting of” and “consistingessentially of” shall be closed or semi-closed transitional phrases,respectively, as set forth in the United States Patent Office Manual ofPatent Examining Procedures, Section 2111.03.

We claim:
 1. A method implemented by one or more processors, the methodcomprising: causing a supply signal to be provided to a first set oflight emitting diodes (LEDs) and a second set of LEDs of a lightingdevice, wherein a subset of the LEDs corresponds to backup LEDs that areconnected to a backup battery of the lighting device; operating thefirst set of LEDs of the lighting device based on a first pulse widthmodulated (PWM) signal generated at the lighting device; operating thesecond set of LEDs of the lighting device based on a second pulse widthmodulated signal generated at the lighting device; determining, based onsensor data provided by one or more sensors of the lighting device, thata motion event has occurred proximate to the lighting device; operatingat least one of the first set of LEDs and the second set of LEDs of thelighting device in response to the motion event, wherein the at leastone of the first set of LEDs and the second set of LEDs are operatedaccording to at least one of the first PWM signal and the second PWMsignal; determining that a power source for the supply signal is atleast temporarily unavailable, wherein the power source is connected tothe backup LEDs at a node to which the backup battery is connected;providing by the backup battery a backup supply signal to the backupLEDs, wherein the backup supply signal bypasses LEDs of the first setand of the second set of LEDs that are excluded from the backup LEDs;operating the backup LEDs from a current for a backup PWM signal whichoperates according to a predetermined backup power duty cycle.
 2. Themethod of claim 1 wherein the first PWM signal and the second PWM signalare different.
 3. The method of claim 2 wherein the backup PWM signal isdifferent from one of the first PWM signal and the second PWM signal. 4.The method of claim 3, further comprising: determining a temperature ofthe backup battery; and causing the backup battery to provide lesselectrical current in the backup supply signal to the backup LEDs inresponse to the determined temperature meeting a predeterminedcondition.
 5. The method of claim 3, further comprising: subsequent tothe backup battery providing the backup supply signal to the backupLEDs, determining that the power source is available for providing powerto the lighting device; and causing the power source to charge thebackup battery.
 6. The method of claim 5, further comprising: causingthe power source to provide power to the first set of LEDs and thesecond set of LEDs while also charging the backup battery.
 7. The methodof claim 1 wherein a first duty cycle at which the first PWM signaloperates is greater than the predetermined backup power duty cycle.
 8. Amethod implemented by one or more processors, the method comprising:causing a supply signal to be provided to a first set of light emittingdiodes (LEDs) and a second set of LEDs of a lighting device, wherein asubset of the first set of LEDs corresponds to backup LEDs that areconnected to a backup battery of the lighting device; determining that apower source for the supply signal is at least temporarily unavailable,wherein the power source is connected to the backup LEDs at a node towhich the backup battery is connected; and causing the backup battery toprovide a backup supply signal to the backup LEDs of the first set ofLEDs, wherein the backup supply signal bypasses LEDs of the first set ofLEDs that are excluded from the backup LEDs, at least based on anarrangement of the backup LEDs.
 9. The method of claim 8, furthercomprising: determining that an ambient temperature at a location of thelighting device is outside of an operating temperature range for thebackup battery; and causing the backup battery to provide lesselectrical current to the backup LEDs in response to the ambienttemperature being outside of the operating temperature range for thebackup battery.
 10. The method of claim 8, further comprising:subsequent to the backup battery providing the backup supply signal tothe backup LEDs, determining that the power source is available forproviding power to the lighting device; and causing the power source tocharge the backup battery.
 11. The method of claim 10, furthercomprising: causing the power source to provide power to the first setof LEDs and the second set of LEDs while also charging the backupbattery.
 12. The method of claim 8, wherein the first set of LEDs andthe second set of LEDs are separate.
 13. A system, comprising: a firstset of light emitting diodes (LEDs), a second set of LEDs, and a backupset of LEDs which are a subset of the LEDs and that are connected to abackup battery of a lighting device; a controller operable to: operatethe first set of LEDs of the lighting device based on a first pulsewidth modulated (PWM) signal generated at the lighting device;determine, based on sensor data provided by one or more sensors of thelighting device, that a motion event has occurred proximate to thelighting device; operate the second set of LEDs of the lighting devicein response to the motion event, wherein the second set of LEDs areoperated according to a second pulse width modulated signal; determinethat a power source is at least temporarily unavailable, wherein thepower source is connected to the backup set of LEDs at a node to whichthe backup battery is connected; provide by the backup battery a backupsupply signal to the backup set of LEDs, wherein the backup supplysignal bypasses LEDs of the first set and the second set of LEDs thatare excluded from the backup set of LEDs and operating the backup set ofLEDs from a current for a backup pulse width modulated signal whichoperates according to a duty cycle substantially similar to that whichthe first pulse width modulated signal operates.